rusty saddlehorn
When a person lays on their back and stiffens their tongue, sticking it out as far as possible and their partner straddles the person's face planting their anus on the protruding tongue and riding up and down, thereby doing all the work while the person on the bottom leisurely performs analingus.
She then mounted her husband's face and rode the rusty saddlehorn while he lazily rimmed her.